Materials containing metal oxides, processes for making same, and processes for using same

ABSTRACT

Compositions having a high metal content comprising a metal salt solution, a stabilizer and one or more optional additives, wherein the metal salt solution comprises a metal ion, a counter ion and a solvent. The compositions are useful for forming films on substrates in the manufacture of solid state and integrated circuit devices.

FIELD OF INVENTION

The present invention relates to materials useful in the manufacture ofsolid state and integrated circuit devices; processes for making same;and processes for using same. In particular, the present inventionrelates to materials for forming metal oxide containing films useful inthe manufacture of solid state and integrated circuit devices; processesfor making same; and processes for using same.

BACKGROUND

Metal oxide films are useful in a variety of applications in thesemiconductor industry such as, for example, lithographic hard masks,underlayers for anti-reflective coatings and electro-optical devices.For example, photoresist compositions are used in microlithographyprocesses for making miniaturized electronic components, such as in thefabrication of computer chips and integrated circuits. Generally, a thincoating of a photoresist composition is applied to a substrate, such asa silicon-based wafer used for making integrated circuits. The coatedsubstrate is then baked to remove a desired amount of solvent from thephotoresist. The baked, coated surface of the substrate is thenimage-wise exposed to actinic radiation, such as visible, ultraviolet,extreme ultraviolet, electron beam, particle beam or X-ray radiation.The radiation causes a chemical transformation in the exposed areas ofthe photoresist. The exposed coating is treated with a developersolution to dissolve and remove either the radiation-exposed or theunexposed areas of the photoresist.

The trend towards the miniaturization of semiconductor devices has ledto the use of new photoresists that are sensitive to shorter and shorterwavelengths of radiation and has also led to the use of sophisticatedmultilevel systems to overcome difficulties associated with suchminiaturization.

Absorbing antireflective coatings and underlayers in photolithographyare used to diminish problems that result from radiation that reflectsfrom substrates which often are highly reflective. Reflected radiationresults in thin film interference effects and reflective notching. Thinfilm interference, or standing waves, result in changes in critical linewidth dimensions caused by variations in the total light intensity inthe photoresist film as the thickness of the photoresist changes.Interference of reflected and incident exposure radiation can causestanding wave effects that distort the uniformity of the radiationthrough the thickness. Reflective notching becomes severe as thephotoresist is patterned over reflective substrates containingtopographical features, which scatter light through the photoresistfilm, leading to line width variations and, in extreme cases, formingregions with complete loss of desired dimensions. An antireflectivecoating film coated beneath a photoresist and above a reflectivesubstrate provides significant improvement in lithographic performanceof the photoresist. Typically, the bottom antireflective coating isapplied on the substrate and cured, followed by application of a layerof photoresist. The photoresist is imagewise exposed and developed. Theantireflective coating in the exposed area is then typically dry etchedusing various etching gases, and the photoresist pattern is thustransferred to the substrate.

Underlayers containing high amount of refractory elements can be used ashard masks as well as antireflective coatings. Hard masks are usefulwhen the overlying photoresist is not capable of providing high enoughresistance to dry etching that is used to transfer the image into theunderlying semiconductor substrate. In such circumstances, a hard maskwhose etch resistance is high enough to transfer any patterns createdover it into the underlying semiconductor substrate can be employed.This is possible when the organic photoresist is different enough fromthe underlying hard mask so that an etch gas mixture can be found whichwill allow the transfer of the image in the photoresist into theunderlying hard mask. This patterned hard mask can then be used withappropriate etch conditions and gas mixtures to transfer the image fromthe hard mask into the semiconductor substrate, a task which thephotoresist by itself with a single etch process could not haveaccomplished.

Multiple antireflective layers and underlayers are being used in newlithographic techniques. In cases where the photoresist does not providesufficient dry etch resistance, underlayers and/or antireflectivecoatings for the photoresist that act as a hard mask and are highly etchresistant during substrate etching are preferred. One approach has beento incorporate silicon, titanium, zirconium or other metallic materialsinto a layer beneath the organic photoresist layer. Additionally,another high carbon content antireflective or mask layer may be placedbeneath the metal containing antireflective layer, to create a trilayerof high carbon film/hard mask film/photoresist. Such trilayers can beused to improve the lithographic performance of the imaging process.

Conventional hard masks can be applied by chemical vapor deposition,such as sputtering. However, the relative simplicity of spin coatingversus the aforementioned conventional approaches makes the developmentof a new spin-on hard mask or antireflective coating with highconcentration of metallic materials in the film very desirable.

Underlayer compositions for semiconductor applications containing metaloxides have been shown to provide dry etch resistance as well asantireflective properties. When higher concentrations of metal oxide arepresent in the underlayer, improved etch resistance and thermalconductance can be achieved. Conventional metal oxide compositions,however, have been found to be very unstable to moisture in air creatinga variety of issues, including shelf life stability, coating problemsand performance shortcomings. As well, conventional compositionsgenerally contain non-metal oxide materials such as polymers,crosslinkers and other materials that detract from the metal oxideproperties required for etch resistance and thermal conductivity. Thus,there is an outstanding need to prepare spin-on hard mask,antireflective and other underlayers that contain high levels of stablesoluble metal oxides which are soluble or colloidally stable. It wouldbe advantageous to provide such layers that have a high metal content.In addition, it would be advantageous to provide such layers that haveexcellent moisture resistance. Further, it would be advantageous toprovide such layers with improved etch selectivity to SiOx with CF₄ oroxygen gas.

SUMMARY OF THE INVENTION

In one of its aspects, the present disclosure relates to a compositioncomprising a metal salt solution, a stabilizer and one or more optionaladditives. The metal salt solution comprises a metal ion, a counter ionand a solvent. The metal ion is selected from the group consisting ofZr, Al, Ti, Hf, W, Mo, Sn, In, Ga, Zn and combinations thereof. Thecounter ion is selected from the group consisting of nitrates, sulfates,acetates, fluorinated alkylacetates, fluorinated alkylsulfonates,acrylates, methacrylates and combinations thereof. The optional additiveis selected from the group consisting of catalysts, crosslinkers,photoacid generators, organic polymers, inorganic polymers, surfactants,wetting agents, anti-foam agents, thixotropic agents and combinationsthereof.

In certain variations, the composition has an organic content that is nomore than about 20%, no more than about 10%, or no more than about 5%.

In certain variations, the composition has a total solid content rangingfrom about 2% to about 40%. In other variations, the composition has atotal solid content ranging from about 5% to about 35%. In othervariations, the composition has a total solid content ranging from about5% to about 25%.

In certain variations, the metal ion is Zr. In certain variations, themetal ion is Al.

In certain variations, the counterion is a sulfonate. In othervariations, the counterion is a nitrate.

In certain variations, the metal salt is zirconyl nitrate. In certainvariations, the metal salt is aluminum nitrate. In certain variations,the metal salt is zirconyl methacrylate. In certain variations, themetal salt is aluminum sulfate. In certain variations, the metal salt istitanium oxysulfate. In certain variations, the metal salt is aluminumtrifluoroacetate. In certain variations, the metal salt is aluminumtrifluoromethylsulfonate.

In certain variations, the solvent is water, an alcohol, an ester, analkylcarboxylic acid, a ketone, a lactone, a diketone, or a combinationthereof. In other variations, the solvent is a cyclohexanone, apropylene glycol monomethyl ether acetate (PGMEA), a propylene glycolmonomethyl ether (PGME) or a combination thereof.

In certain variations, the stabilizer includes a lactone. In particularvariations, the lactone is selected from the group consisting ofα-acetolactone, β-propiolactone, gamma-valerolactone,gamma-butyrolactone and combinations thereof. In certain variations, thelactone is present in the composition at a content of no more than 20%.In other variations, the lactone is present in the composition at acontent of no more than 10%.

In certain variations, the stabilizer includes a carboxylic acid. Inparticular variations, the carboxylic acid is selected from the groupconsisting of acetic acid, propionic acid, isobutyric acid andcombinations thereof. In certain variations, the carboxylic acid ispresent in the composition at a content of no more than 20%. In othervariations, the carboxylic acid is present in the composition at acontent of no more than 10%.

In another of its aspects, the present disclosure relates to a processfor making a composition comprising a metal salt solution wherein themetal salt is dissolved in a mixture comprising a solvent and astabilizer to form a solution. In certain variations, the metal salt isdissolved in the solvent prior to adding the stabilizer. In othervariations, the stabilizer is added to the solvent prior to dissolvingthe metal salt in the solvent. In certain variations, the solution isfiltered before the step of adding the stabilizer. In certainvariations, the metal salt is dissolved in a pre-solvent prior todissolving the metal salt in the solvent. In particular variations, thepre-solvent is selected from the group consisting of alcohols, esters,alkylcarboxylic acids, ketones, lactones, diketones, and combinationsthereof. In certain variations, the boiling point of the pre-solvent islower than about 100° C., or lower than about 70° C. In certainvariations, at least a portion of the pre-solvent, or at least about 95%of the pre-solvent, or at least about 98% of the pre-solvent, isremoved. In certain variations, the metal salt-pre-solvent solution isfiltered.

In yet another of its aspects, the present disclosure relates to aprocess for making an aluminum trifluoromethylsulfonate compositionwherein aluminum trifluoromethylsulfonate is dissolved in a mixturecomprising a solvent and a lactone to form a solution of aluminumtrifluoromethylsulfonate in the mixture of the lactone and the solvent.In certain variations, the dissolving step is conducted at 40-60° C. Incertain variations, the dissolving step is conducted for 2-6 hours. Incertain variations, the solution is filtered before the step of addingthe lactone.

In still another of its aspects, the present disclosure relates to aprocess for making a zirconyl nitrate composition wherein zirconylnitrate hydrate is dissolved in a mixture comprising a solvent and acarboxylic acid to form a solution of zirconyl nitrate in the mixture ofthe carboxylic acid and the solvent. In certain variations, the solutionis filtered before the step of adding the carboxylic acid.

In even another of its aspects, the present disclosure relates to aprocess for coating a substrate wherein a composition as describedherein is coated on the substrate; and the coated substrate is heated toform a cured film. In certain embodiments, the metal oxide content ofthe cured film is between 20% and 90% based on the total weight of thecured film. In other variations, the metal oxide content of the curedfilm is between 40% and 85% based on the total weight of the cured film.In certain variations, the coated substrate is heated at a temperaturebetween 150° C. and 500° C. In other variations, the coated substrate isheated at a temperature between 250° C. and 350° C.

DETAILED DESCRIPTION

As used herein, the conjunction “and” is intended to be inclusive andthe conjunction “or” is not intended to be exclusive unless otherwiseindicated. For example, the phrase “or, alternatively” is intended to beexclusive.

As used herein, the term “and/or” refers to any combination of theforegoing elements including using a single element.

As used herein the phrase “high metal oxide content” means a contenthigher than about 50%, preferably higher than about 60%, and morepreferably higher than about 70%, based on weight percentages.

The present disclosure relates to a composition comprising a metal saltsolution; a stabilizer; and one or more optional additives. The metalsalt solution comprises a metal ion, a counter ion; and one or moresolvents.

Suitable metal ions include, but are not limited to, Zr, Al, Ti, Hf, W,Mo, Sn, In, Ga, Zn and combinations thereof. In certain embodiments, themetal ion is Zr. In other embodiments, the metal ion is Al.

More than one metal may be included in the composition depending on thedesired properties of the final crosslinked layer. For example,zirconium and titanium may be combined to give a layer with very goodetch resistance, thermal conductivity and high refractive index.

Suitable counter ions include, but are not limited to, nitrates,sulfates, acetates, fluorinated alkylacetates, fluorinatedalkylsulfonates, acrylates, methacrylates and combinations thereof. Incertain embodiments, the counterion includes, but is not limited to,sulfates. In other embodiments, the couterion includes, but is notlimited to, nitrates.

In select embodiments, the metal salt includes, but is not limited to,zirconyl nitrate, aluminum nitrate, zirconyl methacrylate, aluminumsulfate, titanium oxysulfate, aluminum trifluoroacetate, aluminumtrifluoromethylsulfonate, and combinations thereof. In particular, themetal salt can be zirconyl nitrate. Additionally, the metal salt can bealuminum trifluoromethyl sulfonate.

Suitable solvents include, but are not limited to, solvents that aretypically used in lithographic spin-on processes. Examples of suitablesolvents for the current disclosure include, but are not limited to,ethers, esters, ether esters, ketones, ketone esters, and combinationsthereof. More specifically, suitable solvents include, but are notlimited to, ethylene glycol monoalkyl ethers, diethylene glycol dialkylethers, propylene glycol monoalkyl ethers, propylene glycol dialkylethers, acetate esters, hydroxyacetate esters, lactate esters, ethyleneglycol monoalkylether acetates, propylene glycol monoalkyletheracetates, alkoxyacetate esters, cyclic ketones, non-cyclic ketones,acetoacetate esters, pyruvate esters and propionate esters. Theaforementioned solvents may be used independently or as a mixture of twoor more. Furthermore, in particular embodiments, at least one highboiling point solvent, such as benzylethyl ether, dihexyl ether,diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,acetonylacetone, caproic acid, capric acid, 1-octanol, 1-nonanol, benzylalcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethylmaleate, γ-butyrolactone, ethylene carbonate, propylene carbonate andphenylcellosolve acetate, is added.

In particular, the solvent can include water, alcohols, esters,alkylcarboxylic acids, ketones, lactones, diketones, and combinationsthereof. In a further embodiment, the solvent includes cyclohexanone. Inyet a further embodiment, the solvent includes propylene glycolmonomethyl ether acetate. In still a further embodiment, the solventincludes propylene glycol monomethyl ether. In even a furtherembodiment, the solvent includes propylene glycol monomethyl etheracetate and propylene glycol monomethyl ether. In particularembodiments, the solvent has a boiling point of about 120° or higher, orabout 140° or higher.

In certain embodiments, the stabilizer is selected to enhance desiredproperties in a coating formed from the composition. Accordingly, avariety of stabilizers known in the art can be used. In certainembodiments, the stabilizer includes a lactone. In particular, suitablelactones include, but are not limited to, α-acetolactone,β-propiolactone, gamma-valerolactone, and gamma-butyrolactone. In otherembodiments, the stabilizer includes a carboxylic acid. In particular,suitable carboxylic acids include, but are not limited to, acetic acid,propionic acid, and isobutyric acid. Those skilled in the art wouldappreciate that one or more additional stabilizers can be used in orderto enhance other beneficial properties of the composition and/or finalcoating. Accordingly, in particular embodiments, the stabilizer isselected from the group consisting of α-acetolactone, β-propiolactone,gamma-valerolactone, gamma-butyrolactone, acetic acid, propionic acid,and isobutyric acid.

In certain embodiments, the metal ion is Al and the stabilizer isselected from the group consisting of gamma-valerolactone,α-acetolactone, β-propiolactone, and gamma-butyrolactone. In certainembodiments, the metal ion is Zr and the stabilizer is selected from thegroup consisting of propionic acid, acetic acid, and isobutyric acid.

As would be appreciated by those skilled in the art, the content of thestabilizer in the composition can be varied. In particular embodiments,the stabilizer is present in the composition at a content of no morethan 20%. In other embodiments, the stabilizer is present in thecomposition at a content of no more than 10%.

The one or more optional additives can be selected from a variety ofadditives that enhance the desired properties of the compositions and/orfinal coatings formed from the compositions. In particular, the one ormore optional additives include, but are not limited to, catalysts,crosslinkers, photoacid generators, organic polymers, inorganicpolymers, surfactants, anti-foam agents, thixotropic agents andcombinations thereof.

Suitable catalysts include, but are not limited to, thermal acidgenerators, peroxides and combinations thereof.

A thermal acid generator is a compound which is capable of generating anacidic moiety when heated. The thermal acid generator can be nonionic orionic. Suitable nonionic thermal acid generators include, for example,cyclohexyl p-toluenesulfonate, methyl p-toluenesulfonate, cyclohexyl2,4,6-triisopropylbenzene sulfonate, nitrobenzyl esters, benzointosylate, 2-nitrobenzyl tosylate,tris(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione, alkyl esters oforganic sulfonic acids such as p-toluenesulfonic acid,dodecylbenzenesulfonic acid, oxalic acid, phthalic acid, phosphoricacid, camphorsulfonic acid, 2,4,6-trimethylbenzene sulfonic acid,triisopropylnaphthalene sulfonic acid, 5-nitro-o-toluene sulfonic acid,5-sulfosalicylic acid, 2,5-dimethylbenzene sulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzene sulfonic acid, 3-bromobenzene sulfonicacid, 2-fluorocaprylnaphthalene sulfonic acid, dodecylbenzene sulfonicacid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and their salts, and combinations thereof. Suitable ionicthermal acid generators include, for example, dodecylbenzenesulfonicacid triethylamine salts, dodecylbenzenedisulfonic acid triethylaminesalts, p-toluene sulfonic acid-ammonium salts, sulfonate salts, such ascarbocyclic aryl (e.g., phenyl, napthyl, anthracenyl, etc.) andheteroaryl (e.g., thienyl) sulfonate salts, aliphatic sulfonate saltsand benzenesulfonate salts. The amount of thermal acid generator can bepresent in total amounts of between about 1 about 5% based on solids.

Suitable peroxides include, but are not limited to, inorganic peroxidessuch as hydrogen peroxide, metal peroxides (e.g., peroxides of group Ior group II metals), organic peroxides such as benzoyl peroxide,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-amylperoxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-hexylperoxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-octylperoxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-cumylperoxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-isopropylcumylperoxycarbonyl)benzophenone anddi-t-butyldiperoxyisophthalate, and peroxyacids such asperoxymonosulphuric acid and peroxydisulphuric acid, and combinationsthereof. The amount of peroxide can be present in total amounts ofbetween about 1 about 10% based on solids.

Suitable crosslinkers include, for example, di-, tri-, tetra-, or highermulti-functional ethylenically unsaturated monomers. Crosslinkers usefulin the present disclosure include, for example: trivinylbenzene,divinyltoluene; divinylpyridine, divinylnaphthalene, divinylxylene,ethyleneglycol diacrylate, trimethylolpropane triacrylate,diethyleneglycol divinyl ether, trivinylcyclohexane, allyl methacrylate(“ALMA”), ethyleneglycol dimethacrylate (“EGDMA”), diethyleneglycoldimethacrylate (“DEGDMA”), propyleneglycol dimethacrylate,propyleneglycol diacrylate, trimethylolpropane trimethacrylate(“TMPTMA”), divinyl benzene (“DVB”), glycidyl methacrylate,2,2-dimethylpropane 1,3 diacrylate, 1,3-butylene glycol diacrylate,1,3-butylene glycol dimethacrylate, 1,4-butanediol diacrylate,diethylene glycol diacrylate, diethylene glycol dimethacrylate,1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, tripropyleneglycol diacrylate, triethylene glycol dimethacrylate, tetraethyleneglycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycoldimethacrylate, polyethylene glycol dimethacrylate, ethoxylatedbisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate,polyethylene glycol dimethacrylate, poly(butanediol)diacrylate,pentaerythritol triacrylate, trimethylolpropane triethoxy triacrylate,glyceryl propoxy triacrylate, pentaerythritol tetraacrylate,pentaerythritol tetramethacrylate, dipentaerythritolmonohydroxypentaacrylate, divinyl silane, trivinyl silane, dimethyldivinyl silane, divinyl methyl silane, methyl trivinyl silane, diphenyldivinyl silane, divinyl phenyl silane, trivinyl phenyl silane, divinylmethyl phenyl silane, tetravinyl silane, dimethyl vinyl disiloxane,poly(methyl vinyl siloxane), poly(vinyl hydro siloxane), poly(phenylvinyl siloxane), tetra(C₁-C₈)alkoxyglycoluril such astetramethoxyglycoluril and tetrabutoxyglycoluril, and combinationsthereof. In particular embodiments, crosslinkers include, but are notlimited to, glycouril, malemine, multiepoxy, multihydroxyl, multicarboxylic acid, and combinations thereof. In select embodiments, thecrosslinker is present in an amount of from about 1 to about 10 wt %, orfrom about 2 to about 5 wt % based on the total solids of thecomposition.

A photoacid generator is a compound which is capable of generating anacidic moiety when exposed to activating radiation. Suitable photoacidgenerators include, for example, sulfide and onium type compounds.Photoacid generators include, but are not limited to, diphenyl iodidehexafluorophosphate, diphenyl iodide hexafluoroarsenate, diphenyl iodidehexafluoroantimonate, diphenyl p-methoxyphenyl triflate, diphenylp-toluenyl triflate, diphenyl p-isobutylphenyl triflate, diphenylp-tert-butylphenyl triflate, triphenylsulfonium hexafluororphosphate,triphenylsulfonium hexafluoroarsenate, triphenylsulfoniumhexafluoroantimonate, triphenylsulfonium triflate,(4-tbutylphenyl)tetramethylenesulfonium (3-hydroxyadamantanylester)-tetrafluoro-butanesulfonate),(4-tbutylphenyl)tetramethylenesulfonium (adamantanylester)-tetrafluoro-butanesulfonate) and dibutylnaphthylsulfoniumtriflate. The amount of photoacid generator can be present in totalamounts of between about 1 about 10% based on solids.

The metal oxide compositions of the current disclosure may furthercontain an organic or inorganic polymer capable of crosslinking duringheat treatment, wherein the metal oxide thermally decomposes while thepolymer thermally crosslinks to give a composite film with high metaloxide content. Polymers such as film forming organic or silicon basedpolymers can be used, such as, for example, polyacrylics,polymethacrylates, and condensation polymers such as polyesters, novolacresins, siloxane resins or organosilsesquioxanes. These polymers may beused alone or in combination with each other, depending on the desiredproperties of the final film after curing. These polymers are generallycrosslinking polymers, containing any of a number of the same ordifferent crosslinking substituents, such as, for example, epoxies,hydroxyls, thiols, amines, amides, imides, esters, ethers, ureas,carboxylic acids, anhydrides, and the like. Other examples ofcrosslinking groups include glycidyl ether groups, glycidyl estergroups, glycidyl amino groups, methoxymethyl groups, ethoxy methylgroups, benzyloxymethyl groups, dimethylamino methyl groups,diethylamino methyl groups, dimethylol amino methyl groups, diethylolamino methyl groups, morpholino methyl groups, acetoxymethyl groups,benzyloxy methyl groups, formyl groups, acetyl groups, vinyl groups andisopropenyl groups. Polymers disclosed in U.S. Pat. No. 8,039,201 andincorporated herein by reference may be used.

Suitable organic polymers include, but are not limited to, polyacrylic,polymethacrylate, polyvinylalcohol, polyvinylpyrridone, condensationpolymers and combinations thereof. In addition, suitable condensationpolymers include, but are not limited to, polyester, novolac resin, andcombinations thereof. In particular embodiments, the organic polymerincludes a crosslinkable group. Suitable crosslinkable groups include,but are not limited to, hydroxyls, epoxys, amides, ureas, carboxylicacids, lactones, pyrridones, and combinations thereof. Besides thecrosslinkable groups, the organic polymer can contain fluoroalkyl orfluoroalcohol groups. The amount of organic polymer can be present intotal amounts of between about 3 about 25% based on solids.

Suitable inorganic polymers include, but are not limited to, hydrogensilsesquioxane (HSSQ), methyl silsesquioxane (MSSQ), and combinationsthereof. The amount of inorganic polymer can be present in total amountsof between about 3 about 25% based on solids.

The resist underlayer film-forming composition of the present disclosuremay contain a surfactant as an optional component to improve applicationproperties to a substrate. Examples of the surfactant may include anonionic surfactant including polyoxyethylene alkyl ethers such aspolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether,polyoxyethylene alkyl aryl ethers such as polyoxyethylene octyl phenylether and polyoxyethylene nonyl phenyl ether,polyoxyethylene-polyoxypropylene block copolymers, sorbitan fatty acidesters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trioleate, and sorbitantristearate, and polyoxyethylene sorbitan fatty acid esters such aspolyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, and polyoxyethylene sorbitan tristearate, afluorosurfactant such as EFTOP® EF301, EF303, and EF352 (manufactured byMitsubishi Materials Electronic Chemicals Co., Ltd.), MEGAFAC® F171,F173, R-30, R-30N, and R-40 (manufactured by DIC Corporation), FluoradFC-430 and FC431 (manufactured by Sumitomo 3M, Ltd.), Asahi Guard®AG710, and Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106(manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymerKP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). These surfactantsmay be used singly or two or more of them may be used in combination.When a surfactant is used, the content of the surfactant is, forexample, about 0.01 to about 5% by mass, or about 0.05 to about 2% bymass.

Suitable anti-foam agents include, but are not limited to, siliconesincluding, but not limited to, polysiloxanes, petroleum hydrocarbons,acetylenics, vinyl polymers and polyalkoxylates.

Suitable thixotropic agents include, but are not limited to, anhydroussilica and colloidal silica. In particular, the anhydrous silica canhave silanol groups on the surface thereof in the form of fine powder(average particle size: about 1 to about 50 μm). The amount of thethixotropic agent can be about 1 to about 20, or about 2 to about 10,parts by weight of the total solid of the composition.

Those skilled in the art would appreciate that, when present, thecontent of the one or more optional additives can be varied in order toenhance the desired properties of the composition without deleteriouslyaffecting the overall performance of the composition. For example, thecrosslinkability and optical parameters can be adjusted. The compositioncan be fine-tuned so that films formed from the composition pass soakingtests in the casting solvent without additional crosslinking agentsand/or catalysts. The optical parameters can be adjusted such thatn=1.3-2.3 and k=0-0.8 at 193 nm. In particular embodiments, the one ormore optional additives can be present in the composition at a contentof no more than 30. In further embodiments, the one or more optionaladditives can be present in the composition at a content of no more than20%. In still further embodiments, the one or more optional additivescan be present in the composition at a content of no more than 10%. Inyet further embodiments, the one or more optional additives can bepresent in the composition at a content of no more than 5%. In evenfurther embodiments, the one or more optional additives can be presentin the composition at a content of no more than 1%.

In certain embodiments, the composition has a low organic content. Inparticular embodiments, the presence of organic compounds with highmolecular weights and/or high boiling points, as compared to the solventand the stabilizer, is low. In more specific embodiments, the organiccontent is no more than about 20%, no more than about 10%, or no morethan about 5%.

In certain embodiments, the composition has a total solid contentranging from about 2% to about 40%. In other embodiments, thecomposition has a total solid content ranging from about 5% to about35%.

The present disclosure also relates to a process for making acomposition comprising a metal salt solution. The present invention alsoincludes a process for preparing the metal salt solution in commonorganic solvents, which can remove trace insoluble impurities andimprove the material processing. According to the process, the metalsalt is dissolved in a solvent to form a solution; and a stabilizer isadded. In certain embodiments, the metal salt is dissolved in thesolvent prior to adding the stabilizer. In other embodiments, thestabilizer is added together with the solvent dissolving the metal salt.

In certain embodiments, the metal salt is dissolved in a pre-solventprior to dissolving the metal salt in the solvent. Suitable pre-solventsinclude, but are not limited to, alcohols, esters, ketones, lactones,diketones, and combinations thereof. In certain embodiments, thepre-solvent has a boiling point lower than the boiling point of thesolvent and, in particular, lower than about 100° C. or lower than about70° C. In particular, the pre-solvent can be acetone. The process canalso include the step of filtering the metal salt-pre-solvent solution.

In certain embodiments, at least a portion of the pre-solvent, or atleast about 95% of the pre-solvent, or at least about 98% of thepre-solvent is removed using any of a variety of known methods. Forexample, at least a portion of the pre-solvent can be removed byevaporation. In particular, the evaporation can be carried out using arotary evaporator.

In addition, the present disclosure relates to a process for making analuminum trifluoromethylsulfonate composition wherein aluminumtrifluoromethylsulfonate is dissolved in a mixture comprising a solventand a lactone to form a solution. In particular embodiments, thedissolving step is conducted at 40-60° C. In particular embodiments, thedissolving step is conducted for 2-6 hours. The metal salt is optionallydissolved in a pre-solvent, as described above.

Further, the present disclosure relates to a process for making azirconyl nitrate composition wherein zirconyl nitrate hydrate isdissolved in mixture comprising a solvent and a carboxylic acid to forma solution. In particular embodiments, the dissolving step is conductedat 40-60° C. In particular embodiments, the dissolving step is conductedfor 2-6 hours. The metal salt is optionally dissolved in a pre-solvent,as described above.

Even further, the present disclosure relates to a process for coating asubstrate wherein a composition as described in the present disclosureis applied on the substrate; and the coated substrate is heated to forma cured film. The cured metal oxide film can have a metal content of atleast about 25 wt %, or at least about 50 wt %, or at least about 70 wt%, based on the total weight of the cured film. For example, the curedmetal oxide film can have a metal content of between about 25% to about80%, or about 30% to about 70%, based on the total weight of the curedfilm. In particular, cured zirconium or aluminum oxide films formed fromthe novel composition have a metal content of at least about 30 wt %, orat least about 50 wt %, or at least about 60 wt %, based on the totalweight of the cured film.

Suitable substrates include, but are not limited to, low dielectricconstant materials, silicon, silicon substrates coated with a metalsurface, copper coated silicon wafers, copper, aluminum, polymericresins, silicon dioxide, metals, doped silicon dioxide, silicon nitride,tantalum, polysilicon, ceramics, aluminum/copper mixtures, any of themetal nitrides such as AlN, gallium arsenide and other Group III/Ncompounds. The substrate may also contain antireflective coatings orunderlayers, such as high carbon underlayers coated over the abovementioned substrates. Further, the substrate may comprise any number oflayers made from the materials described above.

The compositions of the current disclosure are coated on the substrateusing techniques well known to those skilled in the art, such asdipping, spin coating, curtain coating, slot coating, spraying and thelike. The film thickness of the coating ranges from about 5 nm to about1000 nm, or about 10 nm to about 500 nm or about 50 nm to 400 nm. Incertain embodiments, the metal ion is Al; the stabilizer is selectedfrom the group consisting of gamma-valerolactone, α-acetolactone,β-propiolactone, and gamma-butyrolactone; and the film thickness is atleast about 10 nm, or at least about 50 nm.

The coated metal oxide composition is then heated (for example, on a hotplate or convection oven) at curing temperatures. The cure temperaturemay be from about 200° C. to about 550° C., or from about 300° C. toabout 450° C. The cure time may be for about 1 to about 10 minutes, orabout 1 to about 2 minutes. The composition may be coated over otherlayers of antireflective coatings, such as a high carbon content(greater than about 80% or about 85% or about 90%) antireflectivecoating. Once cooled, other materials can be coated onto the surface ofthe metal oxide such as, for example, photoresists.

The cured metal oxide film can be removed using a stripping agent,including, for example, 85% phosphoric acid, 3% HF, 10% TMAH, 10%hydrogen peroxide, aqueous alkaline peroxides and combinations thereof.Stripping times range from about 30 seconds to about 120 seconds atabout room temperature to about 70° C., depending on the film curingconditions. However, it will be understood that other strippingprocesses and processing conditions may be employed. For example, thestripper may be diluted, the time may be shortened and/or thetemperature of stripping may be reduced.

The metal oxide compositions of the current disclosure can be used toprepare lithographic antireflective layers and high K dielectricmaterials in electro-optical devices. An underlayer formed from thepresent compositions can have a refractive index (n) ranging from about1.3 to about 2.3 and an extinction coefficient (k) ranging from about 0to about 0.8, at 193 nm exposure wavelength.

The refractive index (n) (refractive index) and k (extinctioncoefficient) are parameters which relate to the complex refractive indexn_(c) as follows:

n _(c) =n−jk

(Handbook of Semiconductor Manufacturing Technology Edited by YoshioNishi et al, Marcel Dekker Inc, 2000 page 205). The n and k values canbe calculated using an ellipsometer, such as the J. A. Woollam VASE32®Ellipsometer. The exact values of the optimum ranges for k and n aredependent on the exposure wavelength used and the type of application.Typically for 193 nm, the preferred range for k is about 0.1 to about0.6, and for 248 nm the preferred range for k is about 0.15 to about0.8, however, other exposure wavelengths such as, for example DUV andbeyond DUV can be used and the compositions tuned to work in conjunctionwith them.

One or more photoresist compositions can be applied over the cured filmof the present disclosure by any of a variety of processes, such as spincoating, and the like, as described herein. After coating, the solventis removed to a level wherein the coating can be properly exposed. Insome cases, a residual of about 5% solvent may remain in the coating,while in other cases less than 1% is desired. Drying can be accomplishedby hot plate heating, convection heating, infrared heating and the like.The coating is imagewise exposed with actinic radiation through a maskcontaining a desired pattern. An edge bead remover may be applied afterthe coating steps to clean the edges of the substrate using processeswell known in the art.

Photoresists can be any of the types used in the semiconductor industry,provided the photoactive compound in the photoresist and theantireflective coating substantially absorb at the exposure wavelengthused for the imaging process. In some embodiments, photoresists usefulfor immersion lithography are used. Typically, photoresists suitable forimaging with immersion lithography may be used, where such photoresistshave a refractive index higher than about 1.85 and also are hydrophobichaving water contact angle in the range of 75° to 95°.

Several major deep ultraviolet (uv) exposure technologies have providedsignificant advancement in miniaturization, and have actinic radiationof 250 nm to 10 nm, such as 248 nm, 193 nm, 157 and 13.5 nm. Chemicallyamplified photoresists are often used. Photoresists for 248 nm havetypically been based on substituted polyhydroxystyrene and itscopolymers/onium salts, such as those described in U.S. Pat. Nos.4,491,628 and 5,350,660. On the other hand, photoresists for exposure at193 nm and 157 nm require non-aromatic polymers since aromatics areopaque at this wavelength. U.S. Pat. Nos. 5,843,624 and 6,866,984disclose photoresists useful for 193 nm exposure. Generally, polymerscontaining alicyclic hydrocarbons are used for photoresists for exposurebelow 200 nm. Alicyclic hydrocarbons are incorporated into the polymerfor many reasons, primarily since they have relatively high carbon tohydrogen ratios which improve etch resistance, but they also providetransparency at low wavelengths and they have relatively high glasstransition temperatures. U.S. Pat. No. 5,843,624 discloses polymers forphotoresists that are obtained by free radical polymerization of maleicanhydride and unsaturated cyclic monomers. Any of the known types of 193nm photoresists may be used, such as those described in U.S. Pat. Nos.6,447,980 and 6,723,488. Two basic classes of photoresists sensitive at157 nm, and based on fluorinated polymers with pendant fluoroalcoholgroups, are known to be substantially transparent at that wavelength.One class of 157 nm fluoroalcohol photoresists is derived from polymerscontaining groups such as fluorinated-norbornenes, and arehomopolymerized or copolymerized with other transparent monomers such astetrafluoroethylene (U.S. Pat. Nos. 6,790,587, and 6,849,377) usingeither metal catalyzed or radical polymerization. Generally, thesematerials give higher absorbencies but have good plasma etch resistancedue to their high alicyclic content. In addition, a class of 157 nmfluoroalcohol polymers has been described in which the polymer backboneis derived from the cyclopolymerization of an asymmetrical diene such as1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene (U.S.Pat. No. 6,818,258) or copolymerization of a fluorodiene with an olefin(U.S. Pat. No. 6,916,590). These materials give acceptable absorbance at157 nm, but due to their lower alicyclic content as compared to thefluoro-norbornene polymer, have lower plasma etch resistance. These twoclasses of polymers can often be blended to provide a balance betweenthe high etch resistance of the first polymer type and the hightransparency at 157 nm of the second polymer type. Photoresists thatabsorb extreme ultraviolet radiation (EUV) of 13.5 nm are also usefuland are known in the art. Thus, photoresists absorbing in the range ofabout 12 nm to about 250 nm are useful.

The novel coatings can also be used in processes with nanoimprinting ande-beam resists.

After the coating process, the photoresist can be imagewise exposed. Theexposure may be done using typical exposure equipment. The exposedphotoresist is then developed in an aqueous developer to remove thetreated photoresist. The developer is preferably an aqueous alkalinesolution comprising, for example, tetramethylammonium hydroxide (TMAH),typically 2.38 wt % TMAH. The developer may further comprisesurfactant(s). An optional heating step can be incorporated into theprocess prior to development and after exposure.

The process of coating and imaging photoresists is well known to thoseskilled in the art and is optimized for the specific type of photoresistused. The photoresist patterned substrate can then be dry etched with anetching gas or mixture of gases, in a suitable etch chamber to removethe exposed portions of the underlayers and optional otherantireflective coatings. Various etching gases are known in the art foretching underlayer coatings, such as those comprising O₂, CF₄, CHF₃,Cl₂, HBr, SO₂, CO, etc. In one embodiment, the article comprises asemiconductor substrate with a high carbon antireflective film, overwhich the film of the present disclosure is coated. A photoresist layeris coated above this. The photoresist is imaged as disclosed above andthe metal underlayer is dry etched using gases comprising fluorocarbons.After the metal underlayer is etched, the high carbon film can be dryetched using oxygen or oxygen mixtures. Advantageously, the film of thepresent disclosure may be removed using a stripper which is a chemicalsolution, as described herein.

Each of the documents referred to above are incorporated herein byreference in its entirety, for all purposes. The following specificexamples will provide detailed illustrations of the methods of producingand utilizing compositions of the present disclosure. These examples arenot intended, however, to limit or restrict the scope of the inventionin any way and should not be construed as providing conditions,parameters or values which must be utilized exclusively in order topractice the present invention.

Examples

Refractive indices (n) and extinction coefficients (k) were measured ona J. A. Woollam VASE32® Ellipsometer.

TGA analysis was done using a Perkin Elmer-TGA7-ThermogravimetericAnalyser in the presence of oxygen from 50-900° C. Images of thecoatings were obtained using scanning electron microscopy (SEM) bycutting the wafers in a direction at a right angle to the longitudinaldirection of the grooves, and observing the sectional groove part usinga scanning electron microscope MODEL S-5000, manufactured by Hitachi,Ltd., at a magnification of 150000 times in a direction perpendicular tothe section.

Formulation and Coating Example 1

20% wt/wt solutions of zirconyl nitrate hydrate ZrO(NO₃)₂.xH₂O (x˜6)from Sigma-Aldrich Corp. was dissolved in a solvent of ArF thinner(PGMEA/PGME 70:30): propionic acid 15:1 and heated to 50° C. withstirring for 6 h. The solution was cooled down, filtered, spin-coated ona silicon wafer and baked at 300° C. for 60 seconds. The coated wafershowed good coating quality by SEM. The refractive index (n) and theabsorption (k) values of the antireflective coating were measured to ben=2.17 and k=0.44 on a J. A. Woollam VASE32 ellipsometer. The sampleswere aged at 40° C. for 1 week. The coating quality and film thicknessat 300° C./60 s have not shown changes by SEM.

Comparative Formulation and Coating Example 1

20% wt/wt solutions of zirconyl nitrate hydrate ZrO(NO₃)₂.xH₂O (x˜6)from Sigma-Aldrich Corp. were dissolved in a solvent of ArF thinner andheated to 50° C. with stirring for 6 h. The solution was cooled down,filtered, spin-coated on a silicon wafer, and baked at 300° C. for 60seconds. The coated wafer shows good coating quality with a filmthickness of 138 nm by SEM. The samples was aged at 40° C. for 1 week.The coating quality and film thickness at 300° C./60 s was evaluated bySEM showing that the film thickness increases to 168 nm (22%difference).

Formulation and Coating Example 2

The 20% wt/wt solution from Formulation and Coating Example 1 wasdiluted to 3.6 wt/wt % in ArF thinner solvent. After sufficient mixing,the solution was filtered, spin-coated on a silicon wafer and baked at300° C. for 60 seconds. The coated wafer shows good coating quality bySEM. The refractive index (n) and the absorption (k) values of theantireflective coating were measured to be n=2.12 and k=0.45 on a J. A.Woollam VASE32 ellipsometer.

Formulation and Coating Example 3

20% wt/wt solutions of Zirconyl nitrate hydrate ZrO(NO₃)₂.xH₂O (x˜6)from Sigma-Aldrich Corp. was dissolved in a solvent of water: propionicacid 15:1 and heated to 50° C. with stirring for 4-5 h. The solution wascooled down and 0.05% of Megafac 82011 (Dainippon ink and Chemicals,Inc.) was mixed in the solution. The solution was filtered andspin-coated on a silicon wafer and baked at 300° C. for 60 seconds. Thecoated wafer shows good coating quality by SEM. The refractive index (n)and the absorption (k) values of the antireflective coating weremeasured to be n=2.14 and k=0.35 on a J. A. Woollam VASE32 ellipsometer.

Formulation and Coating Example 4

5% wt/wt solution of aluminum trifluoromethylsulfonate was dissolved inArF thinner under ultrasonic conditions. After sufficient mixing forseveral days, the solution was filtered and spin-coated on a siliconwafer and baked at 350° C. for 60 seconds. The coated wafer shows goodcoating quality by SEM. The refractive index (n) and the absorption (k)values of the antireflective coating were measured to be n=1.47 andk=0.04 on a J. A. Woollam VASE32 ellipsometer.

Formulation and Coating Example 5

10% wt/wt solution of aluminum trifluoromethylsulfonate was dissolved inArF thinner: gamma-valerolactone (GVL) 90:10, mixed at 50° C. for 6 h,filtered, spin-coated on a silicon wafer and baked at 350° C. for 60seconds. The coated wafer shows good coating quality by SEM. Therefractive index (n) and the absorption (k) values of the antireflectivecoating were measured to be n=1.33 and k=0.01 on a J. A. Woollam VASE32ellipsometer.

Comparative Formulation and Coating Example 5A

10% wt/wt solution of aluminum trifluoromethylsulfonate was dissolved inArF thinner and heated at 50° C. for 6 h. The solution was filtered,spin-coated on a silicon wafer and baked at 350° C. for 60 seconds. Thecoated wafer showed defects by SEM.

Comparative Formulation and Coating Example 5B

10% wt/wt solution of aluminum trifluoromethylsulfonate was dissolved inArF thinner under ultrasonic conditions. The solution was filtered,spin-coated on a silicon wafer and bakes at 350° C. for 60 seconds. Thecoated wafer showed defects by SEM.

Formulation and Coating Example 6

40 g of zirconyl nitrate hydrate ZrO(NO₃)₂.xH₂O (x˜6) from Sigma-AldrichCorp. was dissolved in 160 g of acetone by rolling the mixture solutionover weekend. The solution was then filtered. The solution was thenadded to a 500 mL single neck flask containing 160 g of cyclohexanone.10 g of propionic acid was added to the above mixture slowly and mixedwell. Acetone was evaporated by rotary evaporator. The final solutionwas weighed to be 188 g. The solid content (zirconyl nitrate) wasmeasured to be 12.5%.

Formulation Example 6 was filtered and spin-coated on a silicon waferand bake at 300° C. for 60 seconds. The coated wafer shows good coatingquality by SEM. The refractive index (n) and the absorption (k) valuesof the antireflective coating were measured to be n=2.15 and k=0.44 on aJ. A. Woollam VASE32 ellipsometer.

Formulation and Coating Example 7

40 g of zirconyl nitrate hydrate ZrO(NO₃)₂.xH₂O (x˜6) from Sigma-AldrichCorp. was dissolved in 160 g of acetone by rolling the mixture solutionover weekend. The solution was then filtered. The solution was thenadded to a 500 mL single neck flask containing 160 g of PGMEA/PGME70:30.10 g of propionic acid was added to the above mixture slowly and mixedwell. Acetone was evaporated by rotary evaporator. The final solutionwas weighed to be 190 g. The solid content (zirconyl nitrate) wasmeasured to be 12.6%.

Formulation Example 7 was filtered and spin-coated on a silicon waferand baked at 300° C. for 60 seconds. The coated wafer shows good coatingquality by SEM. The refractive index (n) and the absorption (k) valuesof the antireflective coating were measured to be n=2.16 and k=0.45 on aJ. A. Woollam VASE32 ellipsometer.

Determination of Metal Content in Films after Baking

Formulation examples 1, 3 and 5 were coated on a silicon wafer and bakedat at 250° C./60 s-350° C./60 s. The metal contents in the films weremeasured by elemental analysis and TGA weight loss measurement. Theresults from both measurements were consistent and indicated that themeasured total metal content ranged from 25 to 60 wt % in films at 250°C./60 s-350° C./60 s baking conditions.

Etch Rate Evaluation of Example 1

The bulk etch rates of MHM films including SiO₂ as reference weremeasured on either ICP or CCP etcher at IMEC for various MHM samples.The etch conditions for CF₄ gas is 10 mT/450 W/100V/30 s/100° CF₄/60° C.and the etch time is 30 seconds. The etch rates of MHM material atvarious temperature is tabulated as following.

Process Dry Etch Rate Substrate Condition (nm/min) SiOX 52.2 Coating250° C./120 S 17.9 Example 1 Coating 300° C./120 S 12.0 Example 1Coating 350° C./120 S 5.0 Example 1

The etch rate of the material of the Example 1 demonstrated much betteretch resistance than that of silicon oxide material in CF₄ gas undersimilar conditions. By increasing baking temperature, the etchresistance of MHM materials can be improved especially in plasma gasesdue to higher metal content in the films.

We claim:
 1. A composition comprising: a metal salt solution comprising: a metal ion selected from the group consisting of Zr, Al, Ti, Hf, W, Mo, Sn, In, Ga, Zn and combinations thereof; and a counter ion selected from the group consisting of nitrates, sulfates, acetates, fluorinated alkylacetates, fluorinated alkylsulfonates, acrylates, methacrylates and combinations thereof; and a solvent; a stabilizer; and an optional additive selected from the group consisting of catalysts, crosslinkers, photoacid generators, organic polymers, inorganic polymers, surfactants, wetting agents, anti-foam agents, thixotropic agents and combinations thereof.
 2. The composition of claim 1 wherein the composition has an organic content that is no more than 25%.
 3. The composition of claim 1 having a total solid content ranging from 2% to 40%.
 4. The composition of claim 1 wherein the metal ion is Zr.
 5. The composition of claim 1 wherein the metal ion is Al.
 6. The composition of claim 1 wherein the counterion is selected from the group consisting of alkylsulfonates and nitrates.
 7. The composition of claim 1 wherein the metal salt is selected from the group consisting of zirconyl nitrate, aluminum nitrate, zirconyl methacrylate, aluminum sulfate, titanium oxysulfate, aluminum trifluoroacetate, aluminum trifluoromethylsulfonate, and combinations thereof.
 8. The composition of claim 1 wherein the solvent is selected from the group consisting of water, alcohols, esters, alkylcarboxylic acids, ketones, lactones, diketones, and combinations thereof.
 9. The composition of claim 1 wherein the stabilizer comprises a lactone.
 10. The composition of claim 9 wherein the lactone is selected from the group consisting of α-acetolactone, β-propiolactone, gamma-valerolactone, gamma-butyrolactone and combinations thereof.
 11. The composition of claim 9 wherein the lactone is present in the composition at a content of no more than 20%.
 12. The composition of claim 1 wherein the stabilizer comprises a carboxylic acid.
 13. The composition of claim 12 wherein the carboxylic acid is selected from the group consisting of acetic acid, propionic acid, isobutyric acid and combinations thereof.
 14. The composition of claim 12 wherein the carboxylic acid is present in the composition at a content of no more than 20%.
 15. A process for making a composition comprising a metal salt solution comprising the steps of dissolving the metal salt in a mixture comprising a solvent and a stabilizer to form a solution.
 16. The process of claim 15 wherein the metal salt is dissolved in the solvent prior to adding the stabilizer.
 17. The process of claim 15 wherein the stabilizer is added to the solvent prior to dissolving the metal salt in the solvent.
 18. The process of claim 15 further comprising the step of dissolving the metal salt in a pre-solvent prior to dissolving the metal salt in the solvent.
 19. The process of claim 18 further comprising the step of filtering the solution containing the metal salt and the pre-solvent prior to addition of the stabilizer and the solvent.
 20. The process of claim 19 further comprising the step of removing of the pre-solvent by evaporation from the mixture of metal salt solution.
 21. A process for making an aluminum trifuoromethylsulfonate composition comprising the step of dissolving aluminum trifluoromethylsulfonate in a mixture comprising a solvent and a lactone to form a solution of aluminum trifluoromethylsulfonate in the mixture comprising the lactone and the solvent.
 22. A process for making a zirconyl nitrate composition comprising the step of dissolving zirconyl nitrate hydrate in a mixture comprising a solvent and a carboxylic acid to form a solution of zirconyl nitrate in the mixture comprising the carboxylic acid and the solvent.
 23. A process for coating a substrate comprising the steps of: applying a composition on the substrate; and heating the coated substrate to form a cured film, wherein the composition comprises: a metal salt solution comprising: a metal ion selected from the group consisting of Ti, Zr, Hf, W, Mo, Sn, Al, In, Ga, Zn and combinations thereof; and a counter ion selected from the group consisting of nitrates, sulfates, acetates, fluorinated alkylacetates, fluorinated alkylsulfonates, acrylates, methacrylates and combinations thereof; and a solvent; a stabilizer; and an optional additive selected from the group consisting of catalysts, crosslinkers, photoacid generators, organic polymers, inorganic polymers, surfactants, wetting agents, anti-foam agents, thixotropic agents and combinations thereof. 